JP6763037B2 - Improved eye image processing - Google Patents

Description

The present invention relates to improving the image processing of the eye, and particularly to determining the geometrical measurement value of the eye.

There are various types of imaging devices used to capture images of the eye, such as ophthalmoscopes and fundus cameras. In particular, such a device captures measurements of the retina of the eye, which is a three-dimensional configuration approximated by a sphere. The output of the image apparatus is a two-dimensional image of the three-dimensional retina because the two-dimensional image has many advantages, and in particular, the two-dimensional display can be displayed on a computer screen and output as a photograph or the like. An imaging device examines a three-dimensional retina, eg, scans and produces a two-dimensional image of the retina. When examining the three-dimensional retina, the device introduces distortion as determined by the optical and mechanical properties of the device. This distortion reduces one or more characteristics of the two-dimensional image of the retina, such as maintaining distance, area and angle. When geometric measurements of the retina, such as the distance between two structures of the retina, are required, they are created using two-dimensional images produced by such an imaging device, which causes distortion and inaccuracies. It becomes.

According to the first aspect of the present invention, a method for determining a geometric measurement value of the retina of the eye is provided, and this method is described.
The step of acquiring a two-dimensional display of at least a part of the retina of the eye,
A step of extracting a geometric rearrangement that transforms the two-dimensional display of the retinal part into a three-dimensional display of the retinal part, and
A step of defining the geometric measurements to be captured by the retina in the two-dimensional display using one or more coordinates of the two-dimensional display of the retina portion.
Using the geometric rearrangement, the coordinates of the two-dimensional display of the retinal portion or the coordinates of each of the coordinates are converted into the corresponding coordinates of the three-dimensional display of the retinal portion.
It comprises a step of determining the geometric measurement value of the retina of the eye using the coordinates of the three-dimensional display of the retina portion or the corresponding coordinates of each.

The step of extracting the geometric rearrangement that transforms the 2D display of the retinal part into the 3D display of the retinal part determines the correction of the strain introduced when creating it in the 2D display of the retinal part. Have steps to do. Due to the optical and mechanical properties of the imaging device used to create a two-dimensional display, distortion is introduced in creating it within the two-dimensional display of the retinal portion.

The step of determining the correction of distortion in a two-dimensional display comprises the step of modeling the optical and mechanical properties of the imaging device.

The steps to model the optical and mechanical properties of an imaging device are:
(I) A step of constructing an optical description of an image system including the image device and an eye model.
(Ii) A step of passing a light beam through the image system through the retinal surface of the eye model.
(Iii) A step of calculating the measured value of the light beam on the surface of the retina, and
(Iv) A step of determining the horizontal scanning angle and the vertical scanning angle of the image system with respect to the light beam.
(V) A step of calculating the expected value of the light beam on the retinal surface using the horizontal scanning angle and the vertical scanning angle of the image system.
(Vi) A step of repeating steps (ii) to (v) with respect to a plurality of additional rays, and
(Vii) A step of comparing the actually measured value of the light ray on the retinal surface with the corresponding expected value of the light ray on the retinal surface to determine correction of distortion of the display of the eye in the image apparatus.
To have.

The steps that constitute the optical description of the image system including the image device and the eye model are the step of determining the optical path characteristics of the image device, the step of determining the optical path characteristics of the eye model, and the optical path characteristics of the image system. Provide a step to combine these optical path characteristics to give. The steps for determining the optical path characteristics of the image device include a step of confirming the components of the image device having an optical path effect, a step of confirming the order of the components of the image device, and describing the optical path characteristics over the time of each component. It includes a step of establishing a mathematical function and a step of sequentially combining the optical path characteristics of the components to give the optical path characteristics of the image device. The steps for determining the optical path characteristics of the eye model are the steps for confirming the components of the eye model having an optical path effect, the steps for confirming the order of the components of the eye model, and the optical path characteristics of each component. It includes a step of establishing a mathematical function to be performed and a step of sequentially combining the optical path characteristics of the components to give the optical path characteristics of the eye model.

The passage of light rays through the imaging system onto the retinal surface of the eye model comprises the use of a ray tracing system. The ray tracing system can be a commercially available ray tracing system such as Zemax. The use of a ray tracing system comprises loading an optical description of the image system into the ray tracing system and determining the path for each ray through the image system. The calculation of the measured value of each ray in the retinal portion includes calculating the coordinates of the intersection of each ray with the retinal surface.

The step of determining the horizontal scanning angle with respect to the light ray is the step of confirming the angular position of the horizontal scanning element of the imaging device used to generate the light ray, and the step of using this to determine the horizontal scanning angle with respect to the light ray. It has steps to calculate.

The step of determining the vertical scanning angle of the system with respect to the light beam is the step of confirming the angular position of the vertical scanning element of the imaging device used to generate the light beam, and the step of using this to scan the direction perpendicular to the light beam. It has a step to calculate the angle.

The calculation of the expected value of each ray on the retinal surface comprises calculating the coordinates of the intersection of each ray with the retinal surface using the horizontal and vertical scanning angles of the imaging system.

The step of determining the correction of distortion of the eye display in the imaging device is an analytical transformation that maps the measured value of the ray on the retinal surface of the eye model to the corresponding expected value of the ray on the retinal surface of the eye model. Have steps to get. The step of determining the correction of the distortion of the eye display in the imaging device includes the step of constructing a correction reference table (LUT), and the correction reference table is the retina of the eye model for each of the plurality of rays. It comprises the actual position of the ray on the retinal surface of the eye model with respect to the expected position of the ray on the surface.

The method of determining the correction of the distortion of the two-dimensional display further comprises a step of determining the correction of the distortion of the eye display of the imaging device for a plurality of non-zero gaze angles of the eye model. For each non-zero gaze angle, this method further comprises the step of measuring the gaze angle using the position of the fovea of the eye model. A corrected LUT can be configured for each of the multiple non-zero gaze angles.

The step of determining the correction of distortion in a two-dimensional display is
Steps to create a target and
The step of calculating the image of the target and
A step of scanning the target with an imaging device used to generate the two-dimensional display to create a distorted image of the target.
A step of comparing the calculated image of the target with the distorted image of the target to determine correction of distortion of the image of the image apparatus.
To have.

The step of calculating the target image comprises the step of calculating the coordinates of a plurality of points in the target image. The step of scanning the target comprises passing a plurality of light rays through the image apparatus and determining the coordinates of a plurality of points in the distorted image of the target.

The step of comparing the calculated image of the target with the distorted image of the target comprises comparing the points of the calculated image of the target with the corresponding points of the distorted image of the target.

The step of determining correction for image distortion in an imaging device comprises the step of obtaining an analytical transformation that maps the coordinates of the points of the distorted image of the target to the coordinates of the corresponding points of the calculated image of the target. .. The step of determining correction for image distortion in the imaging device is for each of the multiple possible points of the target's distorted image, with respect to the coordinates of the corresponding points of the target's calculated image, the possible points of the distorted image. Includes steps to build a corrective reference table with the coordinates of.

The target has multiple contrasting shapes. The target has a predetermined pattern on it.

The step of determining the correction of the distortion of the two-dimensional display includes the step of receiving the image of the eye and the step of deforming the image until the correction of the distortion is substantially registered in the image of the eye generated by a known imaging device. Prepare.

The step of determining the correction of the distortion of the two-dimensional display includes a third party for determining the correction, and includes the step of receiving the correction from this third party.

The geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion can take the form of an analytical formula that transforms the coordinates of the two-dimensional display into the corresponding coordinates of the three-dimensional display. The geometric rearrangement takes the form of a reference table that lists the coordinates of the two-dimensional display corresponding to the coordinates of the three-dimensional display. The coordinates of the three-dimensional display can be Cartesian coordinates or polar coordinates.

The coordinates of one or more of the two-dimensional representation of the retinal portion used to define the geometric measurements define one or more points of the two-dimensional representation. The points of the two-dimensional display or each point can be specified using the Cartesian coordinate space. The points of the two-dimensional display or each point can be identified on the screen using a pointing device such as a mouse.

Using geometric rearrangement, the step of converting one or more coordinates of the two-dimensional display of the retinal part to the corresponding coordinates of the three-dimensional display of the retinal part uses geometric rearrangement. 3. It comprises a step of mapping the coordinates of one or more points in the two-dimensional display to the coordinates of one or more corresponding points in the three-dimensional display.

Corresponding points of the three-dimensional display of the retinal portion or each corresponding point includes one or more points in the three-dimensional display. The points of the three-dimensional display or each point are specified using the Cartesian coordinate space. The points of the three-dimensional display or each point can be specified using the polar coordinate space.

The geometrical measurement of the retinal part comprises a measurement of the distance of the structure of the retinal part. Geometric measurements of distance are defined in the two-dimensional display of the retinal portion using the coordinates of the first and second points in the two-dimensional display. Geometric rearrangement can be used to convert the first and second points in the two-dimensional display of the retinal portion to the corresponding first and second points in the three-dimensional display of the retinal portion. Determining a geometric measurement of a distance using the corresponding first and second points of the 3D display defines the starting position using the first point of the 3D display, 3D It includes defining the end position of the measurement using the second point of the display and measuring the distance between the first point and the second point of the three-dimensional display. The three-dimensional representation of the retinal portion is considered to be a sphere, at the distance between the first and second points, measured as the shortest distance between the first and second points of the sphere. is there.

The shortest distance between the first and second points of the sphere is the cosine law for the sphere, ie
Δσ = arccos (sin (φ _s ) sin (φ _f ) + cos (φ _s ) cos (φ _f ) cos (Δλ))
Is measured in units (degrees or radians) with respect to the sphere. Here, Δσ is the central angle between the points, λ _s φ _s and λ _f φ _f are the longitude and latitude of the first point and the second point, respectively, and Δλ is the absolute difference of longitude. is there.

The shortest distance between the first and second points in a sphere, measured in units of sphere, is the center between points given in radians, where d is the distance between points, r is the radius of the sphere, and Δσ is the radius. If it is an angle, it can be converted into a physical unit (mm) using d = rΔσ.

を用いて、球に関する単位（度又はラジアン）で測定される。ここで、Δσは、ポイント間の中心角で、λ_ｓφ_ｓ及びλ_ｆφ_ｆは、それぞれ、第１のポイント及び第２のポイントの経度及び緯度であり、Δλは、経度の絶対差である。 The shortest distance between the first point and the second point on the sphere is Vincenty's formula, ie

Is measured in units (degrees or radians) with respect to the sphere. Here, Δσ is the central angle between the points, λ _s φ _s and λ _f φ _f are the longitude and latitude of the first point and the second point, respectively, and Δλ is the absolute difference of longitude. is there.

The shortest distance between the first and second points in a sphere, measured in units of sphere, is the center between points given in radians, where d is the distance between points, r is the radius of the sphere, and Δσ is the radius. If it is an angle, it can be converted into a physical unit (mm) using d = rΔσ.

Geometric measurements of distance can be output to the user. Geometric measurements of distance can be represented by a two-dimensional representation of the retinal portion. The shortest distance (geodesic) between the first point and the second point in a three-dimensional sphere does not necessarily correspond to a straight line in the two-dimensional display of the retinal portion. Displaying geometrically measured distances in a two-dimensional display parameters the distance between the first and second points in a sphere, calculates multiple midpoints, and uses the points for a two-dimensional display. It is equipped to display the geometric measurement value of the distance in.

The geometric distance of the retinal portion comprises the angle between the first and second structures of the retinal portion. The geometrical measurements of the angle are the coordinates of the first and second points in the two-dimensional display that marks the first structure, and the first and second points in the two-dimensional display that marks the second structure. It is defined by a two-dimensional display of the retinal portion using the coordinates of the three points. Geometric rearrangement is used to convert the first, second, and third points in the two-dimensional display of the retinal portion to the corresponding first, second, and third points in the three-dimensional display of the retinal portion. To do. Determining the geometric measurement of an angle using the corresponding points in the 3D display is to use the 1st and 2nd points in the 3D display to mark the first structure, second. Using the first and third points of the 3D display to mark the structure, and measuring the angle between the second and third points through the first point of the 3D display. Eh. The angle C is Masaya's law, that is,
haversin (c) = haversin (ab) + sin (a) sin (b) haversin (c)
Is measured using.
Here, haversin (x) ≡ sin ² (x / 2), x1 and x2 are the first and second points in the three-dimensional display marking the first structure, and x1 and x3 are the second points. It is a point in the three-dimensional display that marks the structure, where a is the arc length of the survey line between x1 and x2, b is the arc length of the survey line between x1 and x3, and c is the arc length of the survey line between x2 and x3. The arc length of the survey line between.

The geometric measurement of the angle is output to the user. The geometric measurement value of the angle is represented by the two-dimensional display of the retinal portion by representing the side of the angle (the geodesic between x1 and x2 and the geodesic between x1 and x3) in the two-dimensional display.

を用いて測定される。これにより、物理単位（例えば、ｒがｍｍで与えられる場合、ｍｍ^２）の結果を得る。ｒ^２が上式で省略される場合、球に関する単位、すなわち立体角の単位であるステラジアンで結果が得られる。 Geometric measurements of the retinal portion comprise the area of structure of the retinal portion. Geometric measurements of the area are defined in the two-dimensional display of the retinal portion, using the coordinates of multiple points in the two-dimensional display. Geometric rearrangement can be used to transform multiple points in the two-dimensional display of the retinal portion into corresponding multiple points in the three-dimensional display of the retinal portion. Determining a geometric measurement of an area using multiple corresponding points in a 3D display is to define the shape of the structure using multiple points in the 3D display. Equipped to measure the area of. The three-dimensional representation of the part of the retina is considered to be a sphere, the shape of its structure is defined as a polygon, and the area of the polygon is A for the area of the polygon and α _i for the inside of the polygon from 1 to n. Assuming n angles

Is measured using. This gives the result in physical units (eg mm ² if r is given in mm). If r ² is omitted in the above equation, the result is obtained in the unit of sphere, that is, the unit of solid angle, steradian.

Determining a geometrical measurement of an area using multiple corresponding points in a 3D display is to define the shape of the structure using multiple pixels in the 3D display and to sum the area of the pixels. To measure the area of the shape by. The area of a pixel in a three-dimensional display is calculated by assuming that each pixel is a polygon with four points and each point represents one corner of the pixel.

If the three-dimensional representation of the portion of the retina is considered to be a sphere, the radius of the sphere can be determined by measuring the diameter of the eye. If the three-dimensional representation of the portion of the retina is considered to be a sphere, the radius of the sphere can be set to about 12 mm, which is the average radius of the human eye. Even if the radius of the eye is unknown or cannot be estimated, the assumption that the eye is the unit sphere gives a relative measurement to the size of the retinal sphere. The distance on the sphere can be measured in radians or degrees, and the area can be measured in steradians or square degrees.

Acquiring a two-dimensional display of at least a portion of the retina of the eye comprises activating an imaging device to produce a two-dimensional display. Acquiring a two-dimensional display of at least a portion of the retina of the eye comprises receiving a two-dimensional display already generated by the imaging device.

Acquiring a two-dimensional display of at least a part of the retina of the eye comprises receiving a distortion-corrected three-dimensional display of the retina portion, and obtaining a two-dimensional display from the three-dimensional display using image projection. The image projection is selected from a number of known projection methods. The image projection can be either an equiangular projection that preserves the angle in the two-dimensional display, an equirectangular projection that preserves the distance in the two-dimensional display, or an area-conserved projection that preserves the area in the two-dimensional display. Extracting the geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion comprises determining the back projection used in obtaining the two-dimensional display of the retinal portion.

According to a second aspect of the invention, a computer-readable medium is provided that stores program instructions that, when implemented, implement the method according to the first aspect of the invention.

According to a third aspect of the present invention, an image processing system for determining a geometric measurement value of the retina of the eye is provided, and this system is used.
An image device that acquires a two-dimensional display of at least a part of the retina of the eye,
An extraction element that extracts the geometric rearrangement that transforms the two-dimensional display of the retinal part into the three-dimensional display of the retinal part.
Using the coordinates of one or more of the two-dimensional display of the retina portion, a measurement value defining element that defines the geometric measurement value of the retina in the two-dimensional display, and
Using the geometric rearrangement, a rearrangement element that transforms the coordinates of the two-dimensional display of the retinal portion or each coordinate into the coordinates corresponding to the three-dimensional display of the retinal portion.
A measurement value determination element for determining the geometric measurement value of the retina of the eye using the coordinates of the three-dimensional display of the retina portion or each coordinate.
To have.

The measurement element may be provided as software or software and hardware in the imaging device. Extraction elements, rearrangement elements and measurement value determination elements may be provided as software in the imaging apparatus.

The same eye imaged on different conventional imaging devices produces a display of the retina that cannot be directly compared or superposed. This is also true for the same eye display produced by the same conventional imaging device, but with imaging devices with different gaze angles. In the present invention, when converted to a three-dimensional sphere display, the structure of the retina can be measured in equivalent physical units across the imaging device, so that the relationships can be directly compared and extracted. For example, measuring the distance between the center of the optic nerve head and the fovea in the same eye image produced by different imaging devices requires the same distance. Each imaging device has different distortions due to different optical and mechanical components as well as the gaze angle at the time of imaging. It is possible to compensate for these differences by measuring the distance in the same sphere display.

Geometric measurements of the part of the retina of the eye
-Classification of disease / traumatic artifacts in the retinal area,
-Comparison of retinal structure measurements across different imaging devices,
-Long-term tracking of anatomical structures of the retinal part of the eye and geometric changes in lesions (eg, changes in size, orientation, distance),
-Development of treatment plans based on geometric measurements,
-Direct delivery of treatments such as photocoagulation, based on geometric coordinates obtained from geometric measurements.
-Creation of a reference database based on the distribution of geometric measurements of anatomical structures across populations,
Can be used for.

Here, an embodiment of the present invention will be described merely as an example with reference to the accompanying drawings.

FIG. 1 is a schematic view of an image processing system according to a third aspect of the present invention. FIG. 2 is a flowchart showing the method of the first aspect of the present invention.

Referring to FIG. 1, the image processing system includes an image device 10, an extraction element 26, a measurement value defining element 28, a rearrangement element 30, and a measurement value determination element 32. In this embodiment, the measurement value defining element is provided as software and hardware, and the extraction element, the geometric rearrangement element, and the measurement value determination element are provided as software of the image apparatus.

The image apparatus 10 includes an ophthalmoscope. The ophthalmoscope includes a light source 12 that emits beam light 13, and a scanning relay element that includes a first scanning element 14, a second scanning element 16, scanning compensating means 18, and scanning transmitting means 20. The first scanning element 14 includes a revolver polygon mirror, and the second scanning element 16 includes a vibrating plane mirror. The scanning compensating means 18 includes an elliptical mirror, and the scanning transmitting means 20 includes an aspherical mirror.

The light source 12 directs the incident beam light 13 toward the first scanning element 14. This produces a scan of the beam (indicated by rays A, B and C) in the first vertical direction. This incident beam acts on the scan compensating means 18 and is reflected from the second scanning element 16 from there. This produces a scan of the incident beam in the second horizontal direction. Then, the incident beam acts on the scanning transmission means 20 having two focal points, the second scanning element 16 is provided at the first focal point, and the subject's eye 22 is provided at the second focal point. The incident beam from the second scanning element 16 acting on the scanning moving means 20 is directed at the eye 22 and acts on a part of the retina of the eye. The light source 12 and the scanning relay element of the magnifying glass 10 are combined to give a two-dimensional scan of the incident beam light 13 from the apparent point light source, and the two-dimensional scan of the incident beam light from the apparent point light source is performed on the retina of the eye. Tell to. When the incident beam light is scanned across the retina, it is reflected from the retina and transmitted back through the components of the ophthalmoscope 10 and received by one or more detectors (not shown). Produces light. In a raster scanning pattern produced by first and second scanning elements 14, 16 in which the incident beam light from the light source 12 operates perpendicular to each other to receive a representation of the retina portion of the subject's eye 22. It is scanned over the retina and the reflected beam light is received by one or more detectors.

With reference to FIGS. 1 and 2, the imaging device 10 acquires a two-dimensional display of a portion of the three-dimensional retina of the eye 22 (step 34). Extraction element 26 receives a two-dimensional representation of the retinal portion and uses it to extract a geometric rearrangement that transforms the two-dimensional representation of the retinal portion into a three-dimensional representation of the retinal portion (step 36). Geometric rearrangement extraction involves determining the correction of distortion, which is introduced into the 2D display of the retinal portion by the optical and mechanical properties of the imaging device used to produce the 2D display. To prepare.

In the first embodiment, the determination of distortion correction in a two-dimensional display comprises the step of modeling the optical and mechanical properties of the imaging device 10. This is followed by the following steps: An optical description of an imaging system comprising an imaging device 10 and an eye model 2 is first constructed. This includes a step of determining the optical path characteristics of the image apparatus 10, a step of determining the optical path characteristics of the eye model, and a step of combining these optical path characteristics so as to give the optical path characteristics of the image system. The steps for determining the optical path characteristics of the image device 10 include a step of confirming the components of the image device 10 having an optical path effect, a step of confirming the order of the components of the image device 10, and the optical path characteristics over time of each component. It includes a step of establishing a mathematical function for describing the above and a step of sequentially combining the optical path characteristics of the components to give the optical path characteristics of the image apparatus 10. The steps for determining the optical path characteristics of the eye model are the steps for confirming the components of the eye model having an optical path effect, the steps for confirming the order of the components of the eye model, and the optical path characteristics of each component. It includes a step of establishing a mathematical function to be performed and a step of sequentially combining the optical path characteristics of the components to give the optical path characteristics of the eye model.

The optical description of the imaging system is loaded into a ray tracing system such as Zemax, where the rays pass through the imaging system to the retinal surface of the model of the eye, determining the path for the rays through the imaging system. The measured value of the light beam on the retinal surface is calculated as the coordinates of the intersection of the retinal surface and the light ray.

Then, the horizontal scanning angle and the vertical scanning angle of the image system regarding the light rays are determined. This is the step of ascertaining the angular position of the horizontal scanning element of the imaging device used to generate the ray, the step of using it to calculate the horizontal scanning angle for the ray, and the image used to generate the ray. It includes a step of confirming the angular position of the vertical scanning element of the apparatus and a step of calculating the vertical scanning angle with respect to the light ray using the step.

The expected value of light rays on the surface of the retina is calculated using the horizontal and vertical scan angles of the imaging system. It comprises the step of calculating the coordinates of the intersection of the retinal surface and the light beam using the horizontal and vertical scan angles of the imaging system.

The above steps are then repeated for a plurality of additional rays. The measured value of the light beam on the retinal surface is compared with the expected value of the corresponding light ray on the retinal surface to determine the correction of the distortion of the eye display of the image apparatus 10. Distortion correction is an analytical transformation that maps the measured values of the rays on the retinal surface of the eye model to the expected values of the corresponding rays on the retinal surface of the eye model, or for each of the multiple rays of the eye model. It takes the form of a correction reference table (LUT), which comprises the actual position of the ray on the retinal surface of the eye model with respect to the expected position of the ray on the retinal surface. The determination of distortion correction further comprises the step of determining the correction of distortion for multiple non-zero gaze angles of the eye model.

In the second embodiment, the step of determining the distortion of the two-dimensional display has the following steps. First, a target with multiple contrasting shapes is created. Then, the image of the target is calculated. An imaging device 10 used to form a two-dimensional display is used to scan the target and create a distorted image of the target. Finally, the calculated image of the target is compared with the distorted image of the target to determine the correction of the distortion of the image of the image apparatus 10.

Then, using distortion correction, a geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion is extracted. Geometric rearrangement takes the form of an analytical formula that maps the coordinates of the two-dimensional display to the corresponding coordinates of the three-dimensional display.

The two-dimensional display of the retinal portion is accessed by the measurement value defining element 28, and the geometric measurement value of the distance is used in the two-dimensional display of the retinal portion using the coordinates of the first and second points of the two-dimensional display. Specified (step 38). This comprises displaying a two-dimensional display of the retinal portion to the user identifying the first and second points using a pointing device such as a mouse.

The rearrangement element 30 then uses geometric rearrangement to make the first and second points of the two-dimensional display of the retinal portion the corresponding first and second points of the three-dimensional display of the retinal portion. Is converted to (step 40). This comprises using a transformation to map the coordinates of a point in the two-dimensional display to the coordinates of the corresponding point in the three-dimensional display. Points in the three-dimensional display are specified using polar coordinate space.

Then, the measured value determination element 32 determines the distance of the geometrically measured value using the corresponding first and second points of the three-dimensional display (step 40). This is to use the first point of the three-dimensional display to define the start position of the measurement, the second point of the three-dimensional display to define the end position of the measurement, and the structure of the retina of the eye 22. It comprises measuring the distance between the first point and the second point of the three-dimensional display, which is the length of. The three-dimensional representation of the retinal portion is considered to be a sphere, at the distance between the first and second points, measured as the shortest distance between the first and second points of the sphere. is there.

The shortest distance between the first and second points of the sphere is the cosine law for the sphere, ie
Δσ = arccos (sin (φ _s ) sin (φ _f ) + cos (φ _s ) cos (φ _f ) cos (Δλ))
Is measured in units (degrees or radians) with respect to the sphere. Here, Δσ is the central angle between the points, λ _s φ _s and λ _f φ _f are the longitude and latitude of the first point and the second point, respectively, and Δλ is the absolute difference of longitude. is there.

The shortest distance between the first and second points in a sphere, measured in units of sphere, is the center between points given in radians, where d is the distance between points, r is the radius of the sphere, and Δσ is the radius. If it is an angle, it can be converted into a physical unit (mm) using d = rΔσ.

The geometric measurement of distance is the geometric measurement of distance in a two-dimensional display by parameterizing the distance between the first point and the second point in the sphere, calculating multiple intermediate points, and projecting the points. By displaying the value, it is represented by a two-dimensional display of the retinal portion. Then, the geometric measurement value of the distance displayed in the two-dimensional display is displayed to the user.

Claims (37)

A method of determining geometric measurements of the retina of the eye
The step of acquiring a two-dimensional display of at least a part of the retina of the eye,
A step of extracting a geometric rearrangement that transforms the two-dimensional display of the retinal part into a three-dimensional display of the retinal part, and
A step of defining the geometric measurements to be captured by the retina in the two-dimensional display using the first and second coordinates of the two-dimensional display of the retina portion.
A step of converting the first coordinate of the two-dimensional display of the retinal portion to the corresponding first coordinate of the three-dimensional display of the retinal portion using the geometric rearrangement.
A step of converting the second coordinate of the two-dimensional display of the retinal portion to the corresponding second coordinate of the three-dimensional display of the retinal portion using the geometric rearrangement.
A step of determining the geometric measurement value of the retina of the eye using the corresponding first coordinate and the corresponding second coordinate of the three-dimensional display of the retina portion.
With
The step of determining the geometric measurement of the retina of the eye
Parameterizing the distance between the corresponding first coordinate and the corresponding second coordinate,
Calculating multiple midpoints of the corresponding coordinates of the three-dimensional display of the retinal portion, and
Includes determining geometric measurements of the retina of the eye using multiple midpoints of the corresponding coordinates.
A method characterized by that. The step of acquiring a two-dimensional display of at least a portion of the retina of the eye comprises receiving the two-dimensional display from an imaging device.
The method according to claim 1. The step of obtaining a two-dimensional representation of at least a portion of the retina of the eye
Receiving the distortion correction 3D display of the retinal part, and
Acquiring the two-dimensional display from the three-dimensional display using image projection.
The method according to claim 1. The step of extracting the geometric rearrangement that transforms the two-dimensional display of the retinal part into the three-dimensional display of the retinal part is
Including determining the correction of distortion in the two-dimensional display of the retinal portion.
The method according to claim 1. The step of defining the geometric measurements to be captured by the retina in the two-dimensional display using the first and second coordinates of the two-dimensional display of the retina portion is
Defining the starting position of the geometric measurement using the corresponding first coordinate of the three-dimensional display.
The end position of the geometric measurement is defined by using the corresponding second coordinate of the three-dimensional display, and
Including measuring the distance between the corresponding first coordinate and the corresponding second coordinate.
The method according to claim 1. The method according to claim 1, wherein the three-dimensional display of the retinal portion is a sphere having a predetermined radius. Parameterizing the distance between the corresponding first coordinate and the corresponding second coordinate can be
Includes parameterizing the distance of the sphere between the corresponding first coordinate and the corresponding second coordinate.
The method according to claim 6. The method of claim 1, further comprising displaying the geometric measurement of the retina of the eye. A step of receiving the first coordinate and the second coordinate of the two-dimensional display of the retinal portion via the input device, and
The display further comprises the step of providing a geometrical measurement of the retina of the eye based on the first coordinate and the second coordinate.
The method according to claim 1. A system for determining geometric measurements of the retina of the eye
Including processor and memory
The processor
Obtain a two-dimensional representation of at least a portion of the retina of the eye's retina.
The first and second coordinates of the two-dimensional display of the retina portion are used to define the geometric measurements to be captured by the retina in the two-dimensional display.
The first coordinates of the two-dimensional display of the retinal portion are converted into the corresponding first coordinates of the three-dimensional display of the retinal portion.
The second coordinate of the two-dimensional display of the retinal portion is converted into the corresponding second coordinate of the three-dimensional display of the retinal portion.
Parameterize the distance between the corresponding first coordinate and the corresponding second coordinate.
A plurality of intermediate points of the corresponding coordinates of the three-dimensional display of the retinal portion, which are intermediate between the corresponding first coordinates and the corresponding second coordinates, are calculated.
The geometric measurements of the retina of the eye are determined using the plurality of midpoints of the corresponding coordinates.
The system is configured so that. 10. The system of claim 10, further comprising an imaging apparatus configured to produce a two-dimensional representation of at least a portion of the retina of the eye. The processor is further configured to extract a geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion.
The processor
Using the geometric rearrangement, the first coordinates of the two-dimensional display of the retinal portion are converted to the corresponding first coordinates of the three-dimensional display of the retinal portion.
The geometric rearrangement is configured to transform the second coordinate of the two-dimensional display of the retinal portion into the corresponding second coordinate of the three-dimensional display of the retinal portion. ,
The system according to claim 10. The processor
The starting position of the geometric measurement is defined using the corresponding first coordinate of the three-dimensional display.
The end position of the geometric measurement is defined using the corresponding second coordinate of the three-dimensional display.
The distance between the corresponding first coordinate and the corresponding second coordinate of the three-dimensional display is measured.
10. The system of claim 10, further configured as such. The system according to claim 10, wherein the three-dimensional display of the retinal portion is a sphere having a predetermined radius. The processor
It is further configured to parameterize the distance of the sphere between the corresponding first coordinate and the corresponding second coordinate.
The system according to claim 14. A non-temporary computer-readable medium that stores program instructions, said program instructions to the processor when executed by the processor.
Geometric measurements to be taken of at least a portion of the retina part of the retina of the eye, using the first coordinate and the corresponding second coordinates corresponding to the three-dimensional display of the retinal portion, is defined,
Parameterize the distance between the corresponding first coordinate and the corresponding second coordinate.
The intermediate point between the plurality of corresponding coordinates of the three-dimensional display of the retinal portion and the intermediate point between the corresponding first coordinate and the corresponding second coordinate is calculated.
A plurality of midpoints of the corresponding coordinates are used to determine the geometrical measurement of the retina of the eye.
Non-temporary computer-readable medium. The program instruction is further sent to the processor.
To obtain a two-dimensional display of at least a part of the retina of the eye,
A geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion is extracted.
The first and second coordinates of the two-dimensional display of the retina portion are used to define the geometric measurement to be captured by the retina in the two-dimensional display.
Using the geometric rearrangement, the first coordinates of the two-dimensional display of the retinal portion are transformed into the corresponding first coordinates of the three-dimensional display of the retinal portion.
The geometric rearrangement is used to transform the second coordinate of the two-dimensional display of the retinal portion into the corresponding second coordinate of the three-dimensional display of the retinal portion.
The non-temporary computer-readable medium of claim 16. Using the first coordinate and the second coordinate of the two-dimensional display of the retina portion to define the geometrical measurement to be captured by the retina in the two-dimensional display.
The starting position of the geometric measurement is defined using the corresponding first coordinate of the three-dimensional display.
The end position of the geometric measurement is defined by using the corresponding second coordinate of the three-dimensional display.
Including measuring the distance between the corresponding first coordinate and the corresponding second coordinate of the three-dimensional display.
The non-temporary computer-readable medium of claim 17. The program instruction is further sent to the processor.
Displaying the geometric measurement of the retina of the eye,
The non-temporary computer-readable medium of claim 16. The three-dimensional display of the retinal portion is a sphere having a predetermined radius.
The non-temporary computer-readable medium of claim 16. The method of claim 4, wherein determining the correction of distortion in the two-dimensional display of the retinal portion comprises the step of modeling the optical and mechanical properties of the imaging device. Determining the correction of distortion in the two-dimensional display of the retinal portion comprises the step of determining the correction of distortion of the eye display of the imaging device for a plurality of non-zero gaze angles of the eye model. Item 4. The method according to item 4. Determining the correction of distortion in the two-dimensional display of the retinal portion
Steps to create a target and
The step of calculating the image of the target and
A step of scanning the target with an imaging device used to generate the two-dimensional display to create a distorted image of the target.
A step of comparing the calculated image of the target with the distorted image of the target to determine correction of distortion of the image of the image apparatus.
4. The method according to claim 4. Determining the correction of distortion in the two-dimensional display of the retinal portion
The steps to receive the image of the eye and
With the steps of transforming the image until distortion correction is substantially registered in the image of the eye produced by a known imaging device,
4. The method according to claim 4. The method of claim 4, wherein determining the correction of distortion in the two-dimensional display of the retinal portion comprises the step of receiving the correction from a third party that determines the correction. Extracting the geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion includes determining the correction of distortion in the two-dimensional display of the retinal portion. The system according to claim 12. 26. The system of claim 26, wherein determining the correction of distortion in the two-dimensional representation of the retinal portion comprises modeling the optical and mechanical properties of the imaging device. Determining the correction of distortion in the two-dimensional display of the retinal portion comprises determining the correction of distortion of the eye display of the imaging device for multiple non-zero gaze angles of the eye model. Item 26. Determining the correction of distortion in the two-dimensional display of the retinal portion
Creating a target and
Calculating the image of the target and
Scanning the target with an imaging device used to generate the two-dimensional display to create a distorted image of the target.
The calculated image of the target is compared with the distorted image of the target to determine the correction of distortion of the image of the image apparatus.
26. The system according to claim 26. Determining the correction of distortion in the two-dimensional display of the retinal portion
Receiving an image of the eye and
Deformation of the image until distortion correction is substantially registered in the image of the eye produced by a known imaging device,
26. The system according to claim 26. 26. The system of claim 26, wherein determining the correction of distortion in the two-dimensional display of the retinal portion comprises receiving the correction from a third party that determines the correction. Extracting the geometric rearrangement that transforms the two-dimensional display of the retinal portion into the three-dimensional display of the retinal portion includes determining the correction of distortion in the two-dimensional display of the retinal portion. The non-temporary computer-readable medium of claim 17. The non-transitory computer-readable according to claim 32, wherein determining the correction of distortion in the two-dimensional display of the retinal portion comprises modeling the optical and mechanical properties of the imaging device. Medium. Determining the correction of distortion in the two-dimensional display of the retinal portion comprises determining the correction of distortion of the eye display of the imaging device for multiple non-zero gaze angles of the eye model. Item 32, a non-temporary computer-readable medium. Determining the correction of distortion in the two-dimensional display of the retinal portion
Creating a target and
Calculating the image of the target and
Scanning the target with an imaging device used to generate the two-dimensional display to create a distorted image of the target.
The calculated image of the target is compared with the distorted image of the target to determine the correction of distortion of the image of the image apparatus.
A non-temporary computer-readable medium according to claim 32. Determining the correction of distortion in the two-dimensional display of the retinal portion
Receiving an image of the eye and
Deformation of the image until distortion correction is substantially registered in the image of the eye produced by a known imaging device,
A non-temporary computer-readable medium according to claim 32. The non-transitory computer-readable according to claim 32, wherein determining the correction of distortion in the two-dimensional display of the retinal portion comprises receiving the correction from a third party that determines the correction. Medium.

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